JPH0681543B2 - Position detection circuit for non-rectifier DC motor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-commutation system which detects a relative position between a magnet rotor and an armature winding by a back electromotive force induced in an armature winding. The present invention relates to a position detection circuit for a secondary DC motor.

2. Description of the Related Art In recent years, non-rectifier DC motors have been used in various fields because of their high efficiency and their ability to control the number of revolutions simply by changing the applied voltage. However, in general, a non-commutator DC motor is operated by controlling the operation timing and time of a semiconductor switching element, so that a position detecting sensor such as a Hall element is necessary to detect the position of the magnet rotor. However, when it is desired to use the non-rectifier DC motor in a very bad environment such as such an electric compressor, there is a problem in the reliability of the position detecting sensor. Therefore, in recent years, various methods for detecting the relative position of the magnet rotor from the back electromotive force of the armature winding have been proposed.

An example of the conventional position detecting circuit for the above-described commutatorless motor will be described below with reference to the drawings. FIG. 4 is an overall circuit of a non-commutator motor that rotates the magnet rotor by detecting the relative position of the magnet rotor from the back electromotive force of the armature winding. Reference numeral 1 is a DC power supply, and 2 is a semiconductor commutator device formed by connecting _six semiconductor switching elements S _{1 to} S ₆ in a three-phase bridge connection. 3 is an armature winding 4 and a magnet rotor 5
Is a commutatorless DC motor having 6 is an armature winding 4
Is a control circuit for inputting the counter electromotive voltages V _A , V _B , and V _C and generating signals for controlling the semiconductor switching elements S _{1 to} S ₆ of the semiconductor commutator device 2. Control circuit 6 in the above configuration
Detects the relative position of the magnet rotor 5 from the back electromotive force V _A , V _B , V _C of the armature winding 4 and controls the semiconductor switching elements S _{1 to} S ₆ of the semiconductor commutator device 2 to rotate the magnet. Rotate the child 5. However, since a counter electromotive voltage does not appear in the armature winding 4 when the motor is started, a separate starting circuit (for example, low frequency synchronous starting) is required. FIG. 5 shows a conventional position detection circuit for a commutatorless motor. In FIG.
Reference numerals 7 to 9 are primary filters to which the counter electromotive voltages V _A , V _B , and V _C of the armature winding 4 are input. Reference numeral 10 is a neutral point synthesizing circuit for producing neutral points of the outputs of the primary filters 7 to 9. Reference numerals 11 to 13 denote comparators for comparing the outputs of the primary filters 7 to 9 and the neutral point synthesizing circuit 10, respectively.

The operation of the position detecting circuit of the non-rectifier DC motor configured as described above will be described below.

First, the counter electromotive voltages V _A , V _B , and V _C of the armature winding 4 are converted into triangular wave signals having a phase relationship of about 90 ° by passing through the primary filters 7 to 9. The relative position of the magnet rotor 5 can be detected by comparing each triangular wave signal with the output of the neutral point synthesis circuit 4.

Problems to be Solved by the Invention However, in the above-mentioned configuration, the counter electromotive voltages V _A , V _B , and V _C of the armature winding 4 are, for example, spike voltage V _S as shown in FIG. Is superimposed. The width of this spike voltage V _S increases as the load torque of the non-rectifier DC motor 3 increases, and due to its influence, the output phase of the comparators 11 to 13 is as shown in FIG. Come on. That is, the non-commutator motor operates in the advanced phase with respect to the regular commutation timing. When the load torque further increases, the phase advances rapidly. When the load torque exceeds T _A , the phase exceeds 30 ° and the non-rectifier DC motor stops. Therefore
There is a problem that the non-commutator DC motor cannot be rotated with a load torque of T _A or more.

In view of the above problems, the present invention provides a position detecting circuit for a commutatorless DC motor that can rotate the commutatorless DC motor to a higher load torque with a simple circuit configuration.

Means for Solving the Problems In order to solve the above problems, a position detection circuit for a non-rectifier DC motor according to the present invention includes a secondary filter connected to an armature winding and an output of the secondary filter. It has a configuration in which it comprises a comparator that compares two outputs each.

Operation The present invention can rotate the motor to a high torque by utilizing the good high-frequency cutoff characteristic of the secondary filter, making it less susceptible to the spike voltage, reducing the phase shift, in the above-described configuration.

Embodiment With respect to the position detection circuit for a non-rectifier motor according to an embodiment of the present invention, the whole circuit of the non-rectifier motor is the same and only the position detection circuit is different. Therefore, only different points will be described.

FIG. 1 shows a position detecting circuit of a commutatorless motor according to an embodiment of the present invention. In FIG. 1, 14 to 16 are second-order filters to which the back electromotive forces V _A , V _B , and V _C are input, and a filter having substantially first-order integration characteristics (for example, RC integrating circuit) is connected in series. Are connected in two stages. Further, the cutoff frequency of the filter having the substantially first-order integral characteristic is set sufficiently higher than the operating frequency. 17 is a comparator for comparing the output of the secondary filter 14 and the output of the secondary filter 15, and 18 is the output of the secondary filter 15 and the secondary filter
The comparator 19 compares the output of 16 with the output of the secondary filter 16 and the comparator 19 compares with the output of the secondary filter 14.

The operation of the position detecting circuit of the commutatorless motor configured as described above will be described below with reference to FIGS.

First, FIG. 2 shows operation waveforms at points (a) to (i) of the circuit of FIG. 1, and (i) shows a semiconductor switching element which is turned on. The voltage waveforms of the armature winding 4 of the non-rectifier DC motor 3 are as shown in FIGS.
When the voltages (a) to (c) are passed through the secondary filters 14 to 16 shown in FIG. 1, a waveform having a delay of about 90 ° from the original waveform is obtained by the filter having the substantially first-order integral characteristic. To be Further, the waveform is delayed by about 90 ° by the filter having the integral characteristic in the subsequent stage. Therefore, the output waveforms of the secondary filters 14 to 16 are sinusoidal signals whose phases are shifted by about 180 ° from the original waveforms shown in FIGS. 2 (d) to (f). (G) is a comparison between (d) and (e), (h) is a comparison between (e) and (f), and (i) is a comparison between (f) and (d). Here, a method of driving the non-rectifier DC motor will be described. When the magnet rotor 5 rotates, counter electromotive voltages V _{A ′} , V _{B ′} and V _{C ′} are generated in the electromotive winding 4. V
_{A '} = V ・ sin ωt, V _B' = V ・ sin (ωt-120 °), V
_{C ′} = sin (ωt−240 °). This V _A'and V _{B '}
And the semiconductor switching element to be turned on is switched at the intersection of V _{C ′} . For example, for the semiconductor switching element S ₁ is turned on when the condition of _V A _{'> V B'} and _V A _{'> V C'.} The same applies to the semiconductor switching elements S _{2 to} S ₆ below.

However, during actual operation, the armature winding 4 has a waveform added with the operating voltage from the semiconductor commutator device 2 as shown in FIGS. No position signal is obtained by comparison.

Therefore, by passing through the secondary filters 14 to 16, V _A , V _B , V _C
Delay each 180 °. The waveform delayed by 180 ° has the positive and negative relations reversed with respect to the original waveform, but the position obtained by comparison is exactly the same as when comparing the reverse voltage. The (g) ~ semiconductor switching element S ₁ to S ₆ No commutator DC motor 3 by turning on as shown signal based on the (i): (i) is rotated. Here, the secondary filter has better high-frequency cutoff characteristics than the primary filter, and is less susceptible to high frequency components such as the spike voltage V _S shown in FIG. 2 (a). Therefore, the load torque can be improved to T _{B as} shown in FIG. 3B.

As described above, according to this embodiment, rotation can be achieved by providing the secondary filters 14 to 16 connected to the armature winding 4 and the comparators 17 to 19 for comparing the outputs of the secondary filters 14 to 16, respectively. The maximum torque can be improved.

As described above, according to the present invention, the influence of the spike voltage is reduced by providing the secondary filter connected to the armature winding and the comparator for comparing two outputs each of the outputs of the secondary filter. Thus, the maximum torque that the non-commutator motor can rotate can be improved.

[Brief description of drawings]

FIG. 1 is a position detection circuit for a DC motor without commutator in an embodiment of the present invention, FIG. 2 is an operation waveform of each part in FIG. 1, and FIG.
The figure shows the relationship between the load torque and the phase, FIG. 4 is the entire circuit of the non-rectifier DC motor, and FIG. 5 is the position detection circuit of the conventional non-rectifier DC motor. 2 ... Semiconductor commutator device, 4 ... Armature winding, 5
...... Magnet rotor, 14 to 16 ...... Secondary filter, 17 to 19 ......
Comparator.

Claims (1)

[Claims] 1. An armature winding connected to a neutral point and not grounded, 6
A filter having a semiconductor commutator device formed by connecting three semiconductor switching elements in a three-phase bridge and a magnet rotor and having a substantially first-order integral characteristic connected to each of the armature windings is provided. 2 connected in series
A position detection circuit for a non-commutator DC electric motor comprising a secondary filter and a comparator for detecting the rotational position of the magnet rotor by comparing two outputs of the secondary filter.